1. Field of the Invention
This invention relates in general to duplex-transmitter-receiver apparatus and in particular to apparatus wherein only a single oscillator is utilized for the transmitter and receiver for a digitally modulated radio communication system and wherein a number of stations are capable of communicating in the communication system with a transmitter and receiver at each station for transmitting communication and telemetry.
2. Description of the Prior Art
In transmitter-receiver equipment operating in full duplex operation, the utilization of separate oscillators for the transmitter and receivers requires substantial technical and financial expense particularly when the transmitter and receiver equipment operates in the microwave range. A considerable simplification of the technical problems and financial outlay results when a single local oscillator for both the transmitter and receiver is utilized. However, a number of problems occur in that the transmitter modulation produces undesirable intermodulation products in the receiver branch which interfere with the successful operation of the equipment.